Patent GB-286765-A (GB)
Title: A new or improved system and apparatus for operating and controlling level-crossing gates on railways
IPC: B61L29/02
Filed: 1926-12-06
Abstract: 286,765. British Power Railway Signal Co., Ltd., Glenn, S. L., and Pierce, E. E. Dec. 6, 1926. Operating and controlling gates electrically and hydraulically and pneumatically and by hand; indicating and signalling operation of gates; gate holders; stops.-A system and apparatus for operating and controlling level-crossing gates on railways, having power - operated means for moving the gates, power-operated means for unlocking the sets of gate stops and catches, lowering the appropriate set and raising the other set, and relocking both sets, manually-operated means in the signal cabin or equivalent place for controlling the working of the gate and gatestop operating means, and means operated and controlled by the movement of the gates for controlling the gate stop operating means and indicating in the signal cabin or like place the correct working of the gates, is provided with means or apparatus for detecting the gates, the detecting means including means operated and controlled by the gate catches for controlling the working of the operatinng means for the gates and gate stops and catches, and means for indicating in the signal cabin or like place the correct locking of the gate stops and catches. As described, the system comprises the following apparatus represented in the circuit diagram shown in Fig. 14. A gate-operating machine C as described in Specification 286,375 and being an adaptation of the switch machine described in Specification 251,339, [Class 104 (i), Railway and tramway crossings &c.], a gatestop operating machine D that is substantially the same as the switch machine described in Specification 251,339, [Class 104 (i), Railway and tramway crossings &c.], a gate machine control lever A that is substantially the same as the switch lever described in Specification 2887/11, [Class 104 (i), Railway and tramway crossings &c.], a gatestop machine control lever B, similar to the gate machine control lever A; a snap switch E for the control of the gate-stop machine, and similar to the snap portion of the circuit controller shown in Figs. 12 to 15 of Specification 286,362, [Class 105, Railway signals &c.], a circuit controller F, shown also in Fig. 6, for both gate and gate-stop machines; and a set of gate detectors G, and operating gear therefor, shown in Figs. 3 and 5. The gate detectors G are mounted one on each gate 1 at or adjacent the post 2, Figs. 1, 3 and 5. and comprise a casing containing a set of fixed contacts 82, 83, 84 and a slide bar 85, which carries moving contact makers 86, 87 and is connected to a rod 88 guided at its lower end in a hole in a gate shoe 90 on the toe 91 of the gate. The shoes 90 have projections 93, 94 adapted to strike the respective gate stops 5, and the parts 91, 95 are provided to engage the gate catches 6. These catches are counterweighted and when engaging a striking disc 92 are effective to lift the rods 88, 85 and contacts in the detector boxes. In the raised position, the contacts 82, 83 in the gate-stop machine circuit are closed and the contacts 84 in the gate machine circuit are open. The circuit controller F for the gate machine and gate-stop machine is mounted preferably on a gate post 4 so as to be actuated through its crank arm 65, Fig. 6, by the movements of the gate. The arm 65 is secured to a shaft 76 carrying a drum 77 with contact strips adapted to engage with members of fixed spring contacts 66 - - 75, Figs. 6 and 14. The contacts of the circuit controller are so arranged that one set of fixed contacts is made in the normal (closed to traffic) position of the gates, and another set is made in the reverse (open) position, the circuit controller in its normal position closing contacts in circuits of the machines for operating the gates and gate stops. In the fully-home position of the gates, the circuit controller closes contacts in the gate machine circuit in parallel with contacts which are then open at the detectors, these circuits being closed at contacts in the detector whilst the circuit controller, in moving with the gates, opens all the circuits. The snap switch E serves for cutting off current quickly from the motor of the gate-stop machine when the bar of the latter has completed that portion of its movement which unlocks and withdraws the gate catches holding the gate and releases and permits to rise the set of contacts for the new position of the gates. This switch snaps as regards movement in both directions, and comprises a rotary drum with contact strips adapted to bridge fixed spring contacts 37-40, Fig. 14. The operation of the gates by electrical power takes place in the following steps :-With the gates locked in their normal positions, the gate-stop lever when unlocked from conflicting signal levers is first pulled to complete the circuit of the gate-stop machine D, so that its motor will commence operation and move the bar of the machine to unlock the lower gate stops 5 and catches 6 holding the gates. By the time this is effected the snap switch operates to break the motor circuit and the motor then slows down and stops. The lowering of the catches causes the detector slides to drop and thus open the contacts of the gatestop machine motor circuit. On the gate operating lever being pulled, the gate machine C moves the gates into the reverse position until its polechanger is reversed to cut off power from the gate machine motor and close contacts of the indication circuit of the gate machine. The indication current for operating the appropriate relay in the signal cabin 8 will preferably be dynamic, due to the over-running of the motor, as described in Specification 2887/11, [Class 104 (i), Railway and tramway crossings &c.], or it may be a battery current. The operation of the relay causes a solenoid to be energized and the stroke of the gate control lever to be completed. The opening movement of the gates being completed, the circuit-controller contacts in the gate-stop machine circuit will be closed, and. by the raising of the detector slides as the gate passes over the catches, the detector contacts in the gate machine circuit will be broken and those in the gate-stop machine circuit will be completed. The gate-stop machine motor will thus be again energized and the machine then completes its movement to lock up the catcher and stops for the reverse position of the gates, locking down those for the normal position. Nearing completion of its movement the pole-changer of the gate-stop machine D is thrown to cut off its power supply and complete its indication circuit, the stroke of its control lever being completed as in the case of the gate control lever. By a similar sequence of operations the gates are returned to and locked in their normal positions. The sequence of operations previously described for moving the gates to reverse are traced out on the circuit diagram of Fig. 14 as follows:-The gate-stop control lever when pulled to reverse makes the contacts 18<a>, 19<a>, 20<a> bridge the contacts 11<a>, 13<a>, 15<a> and the indication contact 22<a> bridge the contact fingers 21<a>. The circuit of the gate-stop actuating machine is now energized from the positive bus bar 100 through wires 102, 103, safety-coil 104 of indication relay that locks the armature of indication relay until the gate-stop machine has completed its function, through wires 105, 106, magnet coil 107 of indication selector, wires 111, 112, 113. reverse contacts 15a, bridge strips 215<a>, wires 114. 115, through gate-circuit controller contacts 79, 68, wire 116, snap control switch contacts 37, wire 117 to contacts 118 of reverse pole changer, wire 119 and positive motor armature 120, wire 121, hand-operated isolating switch 97a, wires 122, 123, contacts 124, wire 125, motor field, wire 126 to negative bus bar 127. A further circuit is made up in parallel with the motor circuit through pole changer 128 contacts 129, wires 130 and 126 to negative bus bar 127, and the reverse energized solenoid 128 holds closed members 118 and 124 throughout the reverse operating-stroke of the machine. The gate stops are then operated as in the manner previously described and the snap control switch then functions to open contacts 37 and close contacts 38. The current being cut off the stop-actuating machine slows down, the short-circuiting of the motor armature through the resistance 99 by contacts 40 bringing it quickly to rest at mid-stroke. Both sets of polechanging contacts 129, 132 controlling solenoids 128, 133 respectively are bridged to provided a means for "joggling " the gate stop, if necessary, as more fully described in Specification 251,339, [Class 104 (i), Railway and tramway crossings &c.]. The gates being now free to be moved, the gate lever is pulled to reverse position, to energize the circuit of the gate actuating machine. This circuit is almost identical with the corresponding circuit of the gate-stop machine, contacts 11, 13, 15 being closed and the actuating motor being energized from positive bus bar 100 to negative bus bar 127, including gate-circuit controller contacts 80, 70, in a similar manner. Immediately the gates commence their movement the circuit through the circuit controller is opened, while in any intermediate position of the gates the current is completed through the lower contacts 84 and contact members 87 of the gate detectors; this provides that the detectors have been properly actuated during the first interlocking stroke of the machine. 'The gate machine then operates to complete its movement and the throwing over of its pole-changer to reverse cuts off the power from the motor, opening contacts 147, 153 and 161 and closing contacts 162, 163 and 164, thereby reversing the motor connections and closing the indication circuit. The motor now generates on its residual field and indicates back to the cabin through a circuit including wires 154, contacts 80, 71, motor field